The Obama administration’s version of what happened at the U.S. consulate in Benghazi continues to evolve around whatever facts become public on any given day. First it was spontaneous anger over a video that got out of control. Then it was a non pre-meditated terrorist attack that suddenly grew out of an anti-US protest. Here’s the latest story that could affect the spin:

Witnesses of last week’s deadly attack on a U.S. consulate in Libya have told CBS News that the alleged anti-American protest that U.S. officials say morphed into the assault never actually took place.

The new details add to the widening rift between U.S. and Libyan accounts of the attack as Secretary of State Hillary Clinton is expected to brief members of Congress behind closed doors Thursday. On Wednesday, a top U.S. counterterrorism official told lawmakers on Capitol Hill that the assault was “opportunistic,” but a “terrorist attack.”

Clinton’s briefing comes amid calls from Capitol Hill for more information on the attack, and complaints that the Obama administration has not been forthright.

Closing line from the CBS reporter in the clip below: “What’s clear is that the public won’t get a detailed account of what happened until after the election.” And we should expect nothing less from the most transparent administration in history.